Ronald G. Roberson, C.S.P., holds a doctorate from the Pontifical Oriental Institute in Rome. From 1988 to 1992, he was a staff member of the Pontifical Council for Promoting Christian Unity, serving as a liaison to the Orthodox churches. Father Roberson now lives in Washington, D.C., and is associate director of the Secretariat for Ecumenical and Interreligious Affairs at the United States Conference of Catholic Bishops.

An extremely varied and complex history is covered in this work, and I have striven to present it as clearly as possible. I have done my best to remain objective and fair in treating what at times are tragic and painful situations in the history of these churches and the relationships between them. I hope that this survey will in some small way help western Christians to understand more about our sisters and brothers in the East, so that one day the Church might learn  using the image that was often evoked by Pope John Paul II  to again breathe fully with two lungs, one eastern and one western.